b/18001842
I do this in MailTransport, which is only used by POP and IMAP.
I can't log Analytics in SSLSocketFactoryWrapper, because that
is in emailcommon and would cause a circular dependancy between
emailcomman and UnifiedEmail.
This will not yet work for Exchange, because it gets its socket
indirectly through EmailClientConnectionManager, using a
SchemeRegistry. Still, it will be helpful to get this info for POP
and IMAP.
Change-Id: Ibb9d22c83c49d0ba5090295b5321ca6afb09e65b
93a9662d8d